Composite interconnection conduits for hvac systems

ABSTRACT

A heating, ventilation, and/or air conditioning (HVAC) packaged unit includes a first refrigerant circuit component configured to change a temperature or a pressure of a refrigerant flowing through the first refrigerant circuit component and a second refrigerant circuit component configured to change a temperature or a pressure of the refrigerant flowing through the second refrigerant circuit component. The first and the second refrigerant circuit components are within a common refrigerant circuit that is disposed within a common support structure. The HVAC packaged unit also includes an interconnection conduit having a length formed from aluminum, a first end segment coupled to a first end of the length, and a second end segment coupled to a second end of the length. The first end segment and the second end segment are each formed from copper, and the interconnection conduit extends between the first refrigerant circuit component and the second refrigerant circuit component.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation of U.S. patent application Ser. No. 17/473,795,entitled “COMPOSITE INTERCONNECTION CONDUITS FOR HVAC SYSTEMS,” filedSep. 13, 2021, which is a continuation of U.S. patent application Ser.No. 16/289,102, entitled “COMPOSITE INTERCONNECTION CONDUITS FOR HVACSYSTEMS,” filed Feb. 28, 2019, which claims priority from and thebenefit of U.S. Provisional Application No. 62/803,059, entitled“COMPOSITE INTERCONNECTION CONDUITS FOR HVAC SYSTEMS,” filed Feb. 8,2019, each of which is hereby incorporated by reference in its entiretyfor all purposes.

BACKGROUND

The present disclosure relates generally to heating, ventilation, and/orair conditioning (HVAC) systems, and more particularly to compositeinterconnection conduits for HVAC systems.

A wide range of applications exists for HVAC systems. For example,residential, light commercial, commercial, and industrial systems areused to control temperatures and air quality in indoor environments andbuildings. Such systems may be dedicated to either heating or cooling,although systems are common that perform both of these functions. Verygenerally, these systems operate by implementing a thermal cycle inwhich fluids are heated and cooled to provide air flow at desiredtemperature to a controlled space, typically the inside of a residenceor building. For example, a refrigerant circuit may circulate arefrigerant through one or more heat exchangers to exchange thermalenergy between the refrigerant and one or more fluid flows, such as aflow of air. Generally, HVAC systems may include interconnectionconduits formed from materials, such as copper, that fluidly couple theheat exchangers and other components of the refrigerant circuit.Unfortunately, materials traditionally utilized in interconnectionconduits may contribute to an increase in costs and/or weight of HVACsystems.

SUMMARY

In one embodiment of the present disclosure, a heating, ventilation,and/or air conditioning (HVAC) packaged unit includes a firstrefrigerant circuit component configured to change a temperature or apressure of a refrigerant flowing through the first refrigerant circuitcomponent and a second refrigerant circuit component configured tochange a temperature or a pressure of the refrigerant flowing throughthe second refrigerant circuit component. The first refrigerant circuitcomponent and the second refrigerant circuit component are within acommon refrigerant circuit that is disposed within a common supportstructure. The HVAC packaged unit also includes an interconnectionconduit having a length formed from aluminum, a first end segmentcoupled to a first end of the length, and a second end segment coupledto a second end of the length. The first end segment and the second endsegment are each formed from copper, and the interconnection conduitextends between the first refrigerant circuit component and the secondrefrigerant circuit component.

In another embodiment of the present disclosure, a heating, ventilation,and/or air conditioning (HVAC) packaged unit includes an enclosure, afirst refrigerant circuit component having a first end joint, disposedwithin the enclosure, and configured to change an operating condition ofa refrigerant flowing through the first refrigerant circuit component.The HVAC packaged unit includes a second refrigerant circuit componenthaving a second end joint, disposed within the enclosure, and configuredto change the operating condition of the refrigerant flowing through thesecond refrigerant circuit component. The first refrigerant circuitcomponent and the second refrigerant circuit component are within acommon refrigerant circuit. The HVAC packaged unit also includes aninterconnection conduit having a length formed from aluminum, a firstend segment coupled to a first end of the length, and a second endsegment coupled to a second end of the length. The first end segment isbrazed to the first end joint, and the second end segment is brazed tothe second end joint.

In a further embodiment of the present disclosure, a heating,ventilation, and/or air conditioning (HVAC) packaged unit includes afirst refrigerant circuit component configured to change an operatingcondition of a refrigerant flowing through the first refrigerant circuitcomponent and a second refrigerant circuit component configured tochange the operating condition of the refrigerant flowing through thesecond refrigerant circuit component. The first refrigerant circuitcomponent and the second refrigerant circuit component are within acommon refrigerant circuit that is disposed within a common supportstructure. The HVAC packaged unit includes a first interconnectionconduit having a first length formed from aluminum, a first end segmentcoupled to a first end of the first length, and a second end segmentcoupled to a second end of the first length. The HVAC packaged unit alsoincludes a second interconnection conduit having a second length formedfrom aluminum, a third end segment coupled to a third end of the secondlength, and a fourth end segment coupled to a fourth end of the firstlength. The first end segment, the second end segment, the third endsegment, and the fourth end segment are each formed from copper.Additionally, the first interconnection conduit extends between thefirst refrigerant circuit component and the second interconnectionconduit, and the second interconnection conduit extends between thefirst interconnection conduit and the second refrigerant circuitcomponent.

In another embodiment of the present disclosure, a method forconstructing a heating, ventilation, and/or air conditioning (HVAC)packaged unit includes forming an interconnection conduit by brazing afirst end of a first conduit end segment formed from copper to a firstend of a main conduit body formed from aluminum and brazing a first endof a second conduit end segment formed from copper to a second end ofthe main conduit body. The method also includes brazing a second end ofthe first conduit end segment to a first end joint of a firstrefrigerant circuit component. Additionally, the method includes brazinga second end of the second conduit end segment to a second end joint ofa second refrigerant circuit component to form a partial refrigerantcircuit assembly including the interconnection conduit extending betweenthe first refrigerant circuit component and the second refrigerantcircuit component. The method further includes disposing the partialrefrigerant circuit assembly in an enclosure of the HVAC packaged unit.

Other features and advantages of the present application will beapparent from the following, more detailed description of theembodiments, taken in conjunction with the accompanying drawings whichillustrate, by way of example, the principles of the application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of a commercial orindustrial HVAC system, in accordance with an aspect of the presentdisclosure;

FIG. 2 is a perspective cutaway view of an embodiment of a packaged unitof an HVAC system, in accordance with an aspect of the presentdisclosure;

FIG. 3 is a perspective cutaway view of an embodiment of a split systemof an HVAC system, in accordance with an aspect of the presentdisclosure;

FIG. 4 is a schematic diagram of an embodiment of a vapor compressionsystem of an HVAC system, in accordance with an aspect of the presentdisclosure;

FIG. 5 is a perspective view of an embodiment of an HVAC packaged unithaving composite interconnection conduits, in accordance with an aspectof the present disclosure;

FIG. 6 is a schematic side view of an embodiment of a compositeinterconnection conduit and components of an HVAC packaged unit, inaccordance with an aspect of the present disclosure;

FIG. 7 is a schematic side view of an embodiment of a first compositeinterconnection conduit coupled to a second interconnection conduit, inaccordance with an aspect of the present disclosure;

FIG. 8 is a cross-sectional schematic view of an embodiment of a portionof a composite interconnection conduit having a stepped end segmenttransition, in accordance with an aspect of the present disclosure; and

FIG. 9 is a cross-sectional schematic view of an embodiment of a portionof a composite interconnection conduit having a smooth end segmenttransition, in accordance with an aspect of the present disclosure.

DETAILED DESCRIPTION

The present disclosure is directed to composite interconnection conduitsfor an HVAC system. Interconnection conduits fluidly couple componentsof the HVAC system, such as evaporators, compressors, condensers, andexpansion devices of one or multiple refrigerant circuits to enablerefrigerant to cyclically flow therethrough. However, use of entirelycopper interconnection conduits may significantly contribute to both amaterial cost and a weight of an HVAC system. To provide lighter andmore cost effective HVAC systems, the presently-disclosed compositeinterconnection conduits have a main section formed from aluminum andend segments or end portions formed from copper. As discussed in moredetail herein, the end segments may be brazed onto the main sectionduring a manufacturing process, thus enabling pre-formed interconnectionconduits to be assembled with refrigerant circuit components in atraditional copper-to-copper brazing process. That is, because the endsegments of the composite interconnection conduits are formed fromcopper, they may be brazed to copper end segments of the refrigerantcircuit components during assembly of the HVAC system without additionalor specialized brazing techniques. Accordingly, the compositeinterconnection conduits enable a reduction in both material costs andweight of an HVAC system without complicating the assembly process forthe HVAC system.

Turning now to the drawings, FIG. 1 illustrates an embodiment of aheating, ventilation, and/or air conditioning (HVAC) system forenvironmental management that may employ one or more HVAC units. As usedherein, an HVAC system includes any number of components configured toenable regulation of parameters related to climate characteristics, suchas temperature, humidity, air flow, pressure, air quality, and so forth.For example, an “HVAC system” as used herein is defined asconventionally understood and as further described herein. Components orparts of an “HVAC system” may include, but are not limited to, all, someof, or individual parts such as a heat exchanger, a heater, an air flowcontrol device, such as a fan, a sensor configured to detect a climatecharacteristic or operating parameter, a filter, a control deviceconfigured to regulate operation of an HVAC system component, acomponent configured to enable regulation of climate characteristics, ora combination thereof. An “HVAC system” is a system configured toprovide such functions as heating, cooling, ventilation,dehumidification, pressurization, refrigeration, filtration, or anycombination thereof. The embodiments described herein may be utilized ina variety of applications to control climate characteristics, such asresidential, commercial, industrial, transportation, or otherapplications where climate control is desired.

In the illustrated embodiment, a building 10 is air conditioned by asystem that includes an HVAC unit 12. The building 10 may be acommercial structure or a residential structure. As shown, the HVAC unit12 is disposed on the roof of the building 10; however, the HVAC unit 12may be located in other equipment rooms or areas adjacent the building10. The HVAC unit 12 may be a single package unit containing otherequipment, such as a blower, integrated air handler, and/or auxiliaryheating unit. In other embodiments, the HVAC unit 12 may be part of asplit HVAC system, such as the system shown in FIG. 3 , which includesan outdoor HVAC unit 58 and an indoor HVAC unit 56.

The HVAC unit 12 is an air cooled device that implements a refrigerationcycle to provide conditioned air to the building 10. Specifically, theHVAC unit 12 may include one or more heat exchangers across which an airflow is passed to condition the air flow before the air flow is suppliedto the building. In the illustrated embodiment, the HVAC unit 12 is arooftop unit (RTU) that conditions a supply air stream, such asenvironmental air and/or a return air flow from the building 10. Afterthe HVAC unit 12 conditions the air, the air is supplied to the building10 via ductwork 14 extending throughout the building 10 from the HVACunit 12. For example, the ductwork 14 may extend to various individualfloors or other sections of the building 10. In certain embodiments, theHVAC unit 12 may be a heat pump that provides both heating and coolingto the building with one refrigeration circuit configured to operate indifferent modes. In other embodiments, the HVAC unit 12 may include oneor more refrigeration circuits for cooling an air stream and a furnacefor heating the air stream.

A control device 16, one type of which may be a thermostat, may be usedto designate the temperature of the conditioned air. The control device16 also may be used to control the flow of air through the ductwork 14.For example, the control device 16 may be used to regulate operation ofone or more components of the HVAC unit 12 or other components, such asdampers and fans, within the building 10 that may control flow of airthrough and/or from the ductwork 14. In some embodiments, other devicesmay be included in the system, such as pressure and/or temperaturetransducers or switches that sense the temperatures and pressures of thesupply air, return air, and so forth. Moreover, the control device 16may include computer systems that are integrated with or separate fromother building control or monitoring systems, and even systems that areremote from the building 10.

FIG. 2 is a perspective view of an embodiment of the HVAC unit 12. Inthe illustrated embodiment, the HVAC unit 12 is a single package unitthat may include one or more independent refrigeration circuits andcomponents that are tested, charged, wired, piped, and ready forinstallation. The HVAC unit 12 may provide a variety of heating and/orcooling functions, such as cooling only, heating only, cooling withelectric heat, cooling with dehumidification, cooling with gas heat, orcooling with a heat pump. As described above, the HVAC unit 12 maydirectly cool and/or heat an air stream provided to the building 10 tocondition a space in the building 10.

As shown in the illustrated embodiment of FIG. 2 , a cabinet 24 enclosesthe HVAC unit 12 and provides structural support and protection to theinternal components from environmental and other contaminants. In someembodiments, the cabinet 24 may be constructed of galvanized steel andinsulated with aluminum foil faced insulation. Rails 26 may be joined tothe bottom perimeter of the cabinet 24 and provide a foundation for theHVAC unit 12. In certain embodiments, the rails 26 may provide accessfor a forklift and/or overhead rigging to facilitate installation and/orremoval of the HVAC unit 12. In some embodiments, the rails 26 may fitinto “curbs” on the roof to enable the HVAC unit 12 to provide air tothe ductwork 14 from the bottom of the HVAC unit 12 while blockingelements such as rain from leaking into the building 10.

The HVAC unit 12 includes heat exchangers 28 and 30 in fluidcommunication with one or more refrigeration circuits. Tubes within theheat exchangers 28 and 30 may circulate refrigerant, such as R-410A,through the heat exchangers 28 and 30. The tubes may be of varioustypes, such as multichannel tubes, conventional copper or aluminumtubing, and so forth. Together, the heat exchangers 28 and 30 mayimplement a thermal cycle in which the refrigerant undergoes phasechanges and/or temperature changes as it flows through the heatexchangers 28 and 30 to produce heated and/or cooled air. For example,the heat exchanger 28 may function as a condenser where heat is releasedfrom the refrigerant to ambient air, and the heat exchanger 30 mayfunction as an evaporator where the refrigerant absorbs heat to cool anair stream. In other embodiments, the HVAC unit 12 may operate in a heatpump mode where the roles of the heat exchangers 28 and 30 may bereversed. That is, the heat exchanger 28 may function as an evaporatorand the heat exchanger 30 may function as a condenser. In furtherembodiments, the HVAC unit 12 may include a furnace for heating the airstream that is supplied to the building 10. While the illustratedembodiment of FIG. 2 shows the HVAC unit 12 having two of the heatexchangers 28 and 30, in other embodiments, the HVAC unit 12 may includeone heat exchanger or more than two heat exchangers.

The heat exchanger 30 is located within a compartment 31 that separatesthe heat exchanger 30 from the heat exchanger 28. Fans 32 draw air fromthe environment through the heat exchanger 28. Air may be heated and/orcooled as the air flows through the heat exchanger 28 before beingreleased back to the environment surrounding the rooftop unit 12. Ablower assembly 34, powered by a motor 36, draws air through the heatexchanger 30 to heat or cool the air. The heated or cooled air may bedirected to the building 10 by the ductwork 14, which may be connectedto the HVAC unit 12. Before flowing through the heat exchanger 30, theconditioned air flows through one or more filters 38 that may removeparticulates and contaminants from the air. In certain embodiments, thefilters 38 may be disposed on the air intake side of the heat exchanger30 to prevent contaminants from contacting the heat exchanger 30.

The HVAC unit 12 also may include other equipment for implementing thethermal cycle. Compressors 42 increase the pressure and temperature ofthe refrigerant before the refrigerant enters the heat exchanger 28. Thecompressors 42 may be any suitable type of compressors, such as scrollcompressors, rotary compressors, screw compressors, or reciprocatingcompressors. In some embodiments, the compressors 42 may include a pairof hermetic direct drive compressors arranged in a dual stageconfiguration 44. However, in other embodiments, any number of thecompressors 42 may be provided to achieve various stages of heatingand/or cooling. As may be appreciated, additional equipment and devicesmay be included in the HVAC unit 12, such as a solid-core filter drier,a drain pan, a disconnect switch, an economizer, pressure switches,phase monitors, and humidity sensors, among other things.

The HVAC unit 12 may receive power through a terminal block 46. Forexample, a high voltage power source may be connected to the terminalblock 46 to power the equipment. The operation of the HVAC unit 12 maybe governed or regulated by a control board 48. The control board 48 mayinclude control circuitry connected to a thermostat, sensors, andalarms. One or more of these components may be referred to hereinseparately or collectively as the control device 16. The controlcircuitry may be configured to control operation of the equipment,provide alarms, and monitor safety switches. Wiring 49 may connect thecontrol board 48 and the terminal block 46 to the equipment of the HVACunit 12.

FIG. 3 illustrates a residential heating and cooling system 50, also inaccordance with present techniques. The residential heating and coolingsystem 50 may provide heated and cooled air to a residential structure,as well as provide outside air for ventilation and provide improvedindoor air quality (IAQ) through devices such as ultraviolet lights andair filters. In the illustrated embodiment, the residential heating andcooling system 50 is a split HVAC system. In general, a residence 52conditioned by a split HVAC system may include refrigerant conduits 54that operatively couple the indoor unit 56 to the outdoor unit 58. Theindoor unit 56 may be positioned in a utility room, an attic, abasement, and so forth. The outdoor unit 58 is typically situatedadjacent to a side of residence 52 and is covered by a shroud to protectthe system components and to prevent leaves and other debris orcontaminants from entering the unit. The refrigerant conduits 54transfer refrigerant between the indoor unit 56 and the outdoor unit 58,typically transferring primarily liquid refrigerant in one direction andprimarily vaporized refrigerant in an opposite direction.

When the system shown in FIG. 3 is operating as an air conditioner, aheat exchanger 60 in the outdoor unit 58 serves as a condenser forre-condensing vaporized refrigerant flowing from the indoor unit 56 tothe outdoor unit 58 via one of the refrigerant conduits 54. In theseapplications, a heat exchanger 62 of the indoor unit functions as anevaporator. Specifically, the heat exchanger 62 receives liquidrefrigerant, which may be expanded by an expansion device, andevaporates the refrigerant before returning it to the outdoor unit 58.

The outdoor unit 58 draws environmental air through the heat exchanger60 using a fan 64 and expels the air above the outdoor unit 58. Whenoperating as an air conditioner, the air is heated by the heat exchanger60 within the outdoor unit 58 and exits the unit at a temperature higherthan it entered. The indoor unit 56 includes a blower or fan 66 thatdirects air through or across the indoor heat exchanger 62, where theair is cooled when the system is operating in air conditioning mode.Thereafter, the air is passed through ductwork 68 that directs the airto the residence 52. The overall system operates maintain a desiredtemperature as set by a system controller. When the temperature sensedinside the residence 52 is higher than the set point on the thermostat,or a set point plus a small amount, the residential heating and coolingsystem 50 may become operative refrigerate additional air forcirculation through the residence 52. When the temperature reaches theset point, or a set point minus a small amount, the residential heatingand cooling system 50 may stop the refrigeration cycle temporarily.

The residential heating and cooling system 50 may also operate as a heatpump. When operating as a heat pump, the roles of heat exchangers 60 and62 are reversed. That is, the heat exchanger 60 of the outdoor unit 58will serve as an evaporator to evaporate refrigerant and thereby coolair entering the outdoor unit 58 as the air passes over outdoor the heatexchanger 60. The indoor heat exchanger 62 will receive a stream of airblown over it and will heat the air by condensing the refrigerant.

In some embodiments, the indoor unit 56 may include a furnace system 70.For example, the indoor unit 56 may include the furnace system 70 whenthe residential heating and cooling system 50 is not configured tooperate as a heat pump. The furnace system 70 may include a burnerassembly and heat exchanger, among other components, inside the indoorunit 56. Fuel is provided to the burner assembly of the furnace 70 whereit is mixed with air and combusted to form combustion products. Thecombustion products may pass through tubes or piping in a heatexchanger, separate from heat exchanger 62, such that air directed bythe blower 66 passes over the tubes or pipes and extracts heat from thecombustion products. The heated air may then be routed from the furnacesystem 70 to the ductwork 68 for heating the residence 52.

FIG. 4 is an embodiment of a vapor compression system 72 that can beused in any of the systems described above. The vapor compression system72 may circulate a refrigerant through a circuit starting with acompressor 74. The circuit may also include a condenser 76, an expansionvalve(s) or device(s) 78, and an evaporator 80. The vapor compressionsystem 72 may further include a control panel 82 that has an analog todigital (A/D) converter 84, a microprocessor 86, a non-volatile memory88, and/or an interface board 90. The control panel 82 and itscomponents may function to regulate operation of the vapor compressionsystem 72 based on feedback from an operator, from sensors of the vaporcompression system 72 that detect operating conditions, and so forth.

In some embodiments, the vapor compression system 72 may use one or moreof a variable speed drive (VSDs) 92, a motor 94, the compressor 74, thecondenser 76, the expansion valve or device 78, and/or the evaporator80. The motor 94 may drive the compressor 74 and may be powered by thevariable speed drive (VSD) 92. The VSD 92 receives alternating current(AC) power having a particular fixed line voltage and fixed linefrequency from an AC power source, and provides power having a variablevoltage and frequency to the motor 94. In other embodiments, the motor94 may be powered directly from an AC or direct current (DC) powersource. The motor 94 may include any type of electric motor that can bepowered by a VSD or directly from an AC or DC power source, such as aswitched reluctance motor, an induction motor, an electronicallycommutated permanent magnet motor, or another suitable motor.

The compressor 74 compresses a refrigerant vapor and delivers the vaporto the condenser 76 through a discharge passage. In some embodiments,the compressor 74 may be a centrifugal compressor. The refrigerant vapordelivered by the compressor 74 to the condenser 76 may transfer heat toa fluid passing across the condenser 76, such as ambient orenvironmental air 96. The refrigerant vapor may condense to arefrigerant liquid in the condenser 76 as a result of thermal heattransfer with the environmental air 96. The liquid refrigerant from thecondenser 76 may flow through the expansion device 78 to the evaporator80.

The liquid refrigerant delivered to the evaporator 80 may absorb heatfrom another air stream, such as a supply air stream 98 provided to thebuilding 10 or the residence 52. For example, the supply air stream 98may include ambient or environmental air, return air from a building, ora combination of the two. The liquid refrigerant in the evaporator 80may undergo a phase change from the liquid refrigerant to a refrigerantvapor. In this manner, the evaporator 80 may reduce the temperature ofthe supply air stream 98 via thermal heat transfer with the refrigerant.Thereafter, the vapor refrigerant exits the evaporator 80 and returns tothe compressor 74 by a suction line to complete the cycle.

In some embodiments, the vapor compression system 72 may further includea reheat coil in addition to the evaporator 80. For example, the reheatcoil may be positioned downstream of the evaporator relative to thesupply air stream 98 and may reheat the supply air stream 98 when thesupply air stream 98 is overcooled to remove humidity from the supplyair stream 98 before the supply air stream 98 is directed to thebuilding 10 or the residence 52.

It should be appreciated that any of the features described herein maybe incorporated with the HVAC unit 12, the residential heating andcooling system 50, or other HVAC systems. Additionally, while thefeatures disclosed herein are described in the context of embodimentsthat directly heat and cool a supply air stream provided to a buildingor other load, embodiments of the present disclosure may be applicableto other HVAC systems as well. For example, the features describedherein may be applied to mechanical cooling systems, free coolingsystems, chiller systems, or other heat pump or refrigerationapplications.

FIG. 5 is a perspective view of an embodiment of an HVAC packaged unit100 having composite interconnection conduits, or composite conduits102, in accordance with an aspect of the present disclosure. Forclarity, the HVAC packaged unit 100 is illustrated with an enclosureremoved therefrom, although it is to be understood that any suitableenclosure, such as the cabinet 24 discussed above with reference to FIG.2 , may be disposed around the illustrated components of the HVACpackaged unit 100. The HVAC packaged unit 100 includes refrigerantcircuit components, referred to herein as components 106, such as anevaporator 110, a condenser 112, compressors 114, and expansion devices116. These components 106 operate similar to the previously introducedevaporators, condensers, compressors, and expansion devices of FIGS. 1-4. That is, each component 106 is configured to adjust an operatingcondition, such as a temperature, a pressure, or both, of a refrigerantflowing through the respective component 106. Moreover, because thecomponents 106 are integrated within a common support structure, such asdisposed within a common enclosure, the HVAC packaged unit 100 mayeffectively condition an interior space of the building 10 from outsideof the interior space. For example, in some embodiments, the HVACpackaged unit 100 is a rooftop unit disposed on a rooftop of thebuilding 10. In other embodiments, the HVAC packaged unit 100 may bepositioned on a surface adjacent to the building 10 or within anunoccupied space within the building 10.

As previously mentioned, the composite conduits 102 fluidly couple thecomponents 106 into a refrigerant circuit that enables the HVAC packagedunit 100 to condition the interior space of the building 10. It shouldbe understood that the HVAC packaged unit 100 may include any suitablesingle or multiple refrigerant circuits having any suitable components106 that are operably coupled to one another by the composite conduits102. In contrast to the components 106, the composite conduits 102 donot substantially adjust the operating conditions of the refrigerantflowing through the composite conduits 102. As such, the compositeconduits 102 are not configured for enabling the refrigerant to exchangeheat with another fluid. Therefore, a material having a lower heatconductivity than copper may be utilized in the composite conduits 102.

Accordingly, the composite conduits 102 generally include main bodiesformed from aluminum and pre-brazed end segments formed from copper.During assembly of the HVAC packaged unit 100, a technician maytherefore use traditional copper-to-copper brazing techniques to couplethe end segments of the composite conduits 102 to copper end joints orstubs of the components 106. In some embodiments, the HVAC packaged unit100 additionally includes copper interconnection conduits that fluidlycouple a first portion of the components 106 together in combinationwith the composite conduits 102 that fluidly couple a second portion ofthe components 106 together.

It should be understood that the aluminum material discussed herein maybe any suitable aluminum-containing alloy, and similarly, that thecopper material discussed herein may be any suitable copper-containingalloy. Moreover, although the discussion herein is focused on compositeconduits 102 having main bodies formed from aluminum and pre-brazed endsegments formed from copper, the techniques herein may be extended toany suitable combination of metals or alloys that enable end segments tobe pre-brazed onto main bodies of the composite conduit 102. That is,the material for the end segments may be selected to correspond to thematerial of the end joints of the components 106, and the material forthe main body may be selected based on its respective lower weight andlower cost than the material of the end segments.

With the above in mind, FIG. 6 is a schematic side view of an embodimentof one of the composite conduits 102 and two components 106 of the HVACpackaged unit 100, in accordance with an aspect of the presentdisclosure. Generally, the composite conduit 102 includes a main body130 with a main body length 132 formed from aluminum. The compositeconduit 102 is cylindrically-shaped in the present embodiment, though itshould be understood that the composite conduit 102 may have anysuitable tubular or other fluid-containing shape. As illustrated, afirst end segment 134A or end portion of the composite conduit 102 iscoupled to a first end 136A of the main body 130. Additionally, a secondend segment 134B or end portion of the composite conduit 102 is coupledto a second end 136B of the main body 130. The end segments 134A, 134Bare each formed from copper. Additionally, in the present embodiment,the end segments 134A, 134B each have an end segment length 144 that isless than the main body length 132, conserving the use of copper intoportions of the composite conduit 102 that are to be coupled to thecomponents 106. In some embodiments, the end segment length 144 is anysuitable length that is less than the main body length 132. For example,in some embodiments, the end segment length 144 of each end segment134A, 134B is 4 inches, 5 inches, 6 inches, 7 inches, 8 inches, or more,and the main body length 132 is 2 feet, 4 feet, 6 feet, 8 feet, or more.Moreover, the respective lengths 132, 144 of the composite conduit 102portions each extend along a refrigerant flow direction 140, in thepresent embodiment.

To join the end segments 134A, 134B to the main body 130 of thecomposite conduit 102, copper-to-aluminum brazing techniques may beemployed. That is, each end segment 134A, 134B may be brazed or coupledto one of the ends 136A, 136B of the main body 130, resulting in thecomposite conduit 102 that is lighter and has a lower material cost thana corresponding interconnection conduit fully formed from copper.Because a target temperature range for copper-to-aluminum brazing may besmaller than that of copper-to-copper brazing, pre-forming the compositeconduits 102 during a manufacturing phase of the HVAC packaged unit 100may desirably reduce a demand for practice changes at a later assemblyphase of the HVAC packaged unit 100. Notably, the end segments 134A,134B remain “segments” of the composite conduit 102 even after the endsegments 13A, 134B are brazed to the main body 130 of the compositeconduit 102. In other embodiments, any other suitable coupling processfor joining the end segments 134A, 134B to the main body 130 may beused, such as welding, adhesives, mechanical locking interfaces, and soforth.

Moreover, the composite conduit 102 may be shaped by any suitablebending machine or device. In some embodiments, a manufacturer may use abending machine, which is separate from a bending machine used forcopper conduits, to introduce bends along the main body length 132 ofthe composite conduit 102. Such a practice may reduce or eliminatecross-contamination between copper and aluminum materials that mayotherwise cause galvanic corrosion in the copper and aluminum materials.Additionally, due to limitations on physical space, certain bendingmachines may have a length threshold above which the composite conduit102 may become too unwieldy to manage.

Accordingly, it may be efficient to manufacture composite conduits 102of various standard lengths below the length threshold of the bendingmachine. Then, any desired bends may be introduced in the compositeconduits 102. As discussed below, the pre-bent composite conduits 102may then be coupled to the components 106 of the HVAC packaged unit 100.Additionally, as discussed below with reference to FIG. 7 , thecomposite conduits 102 may also be coupled to additional compositeconduits 102 to form a compound composite conduit that may have a lengththat is longer than the length threshold of the bending machine.

After the composite conduit 102 is formed, the composite conduit 102 maybe coupled between any desired components 106 introduced above, such asa first component 106A and a second component 106B. In the illustratedembodiment, the first component 106A includes a first end joint 150A,and the second component 106B includes a second end joint 150B. Each endjoint 150A, 150B is formed from copper in the present embodiment,thereby enabling a technician to efficiently braze the first end segment134A the first end joint 150A. In this embodiment, the second endsegment 134B may be similarly brazed to the second end joint 150B,thereby extending the composite conduit 102 between the first component106A and the second component 106B. A partial refrigerant circuitassembly is thereby formed. However, it is to be understood that, incertain embodiments having a component 106 with an end joint 150 formedfrom aluminum, the second end segment 134B of the composite conduit 102may be omitted, and the second end 136B of the main body 130 may bebrazed directly to the end joint 150 formed from aluminum.

FIG. 7 is a schematic side view of an embodiment of a first compositeconduit 102A coupled to a second composite conduit 102B, in accordancewith an aspect of the present disclosure. The first composite conduit102A corresponds to the composite conduit 102 discussed above withreference to FIG. 6 , and as such, includes a first main body 130Ahaving a first main body length 132A formed from aluminum. The firstcomposite conduit 102A also includes a first end segment 134A coupled toa first end 136A of the first main body 130A and a second end segment134B coupled to a second end 136B of the first main body 130A.Similarly, the second composite conduit 102B includes a second main body130B formed from aluminum, a third end segment 134C coupled to a thirdend 136C of the second main body 130B, and a fourth end segment 134Dcoupled to a fourth end 136D of the second main body 130B.

Moreover, the second composite conduit 102B also includes a bend 160formed between the third end 136C and the fourth end 136D of the secondmain body 130B. As such, the second main body 130B includes a secondmain body length 132B that meets a third main body length 132C at anangle 164. Although the second composite conduit 102B includes the bend160 with the angle 164 that is approximately 90 degrees in the presentembodiment, it is to be understood that any suitable number of bends 160having any suitable angles 164 or target angles may be included in thecomposite conduits 102 of the HVAC packaged unit 100. As used herein, anangle that is described as “approximately” a particular value isintended to refer to an angle that is within 5% of the particular value.Moreover, the bend 160 may be formed such that a shape of the secondcomposite conduit 102B corresponds to a geometry of the enclosure of theHVAC packaged unit 100.

To enable efficient coupling of the composite conduits 102A, 102B to oneanother, to components 106 of the HVAC packaged unit 100, or both, theend segments 134A, 134B, 134C, 134D are each formed from copper. Forexample, as illustrated, the second end segment 134B of the firstcomposite conduit 102A is coupled to the third end segment 134C of thesecond composite conduit 102B. Accordingly, a resulting compoundcomposite conduit 166 has an effective length that is longer than atotal length of either composite conduit 102A, 102B. In someembodiments, the effective length may also be longer than the thresholdlength of the bending machine discussed above. With the desired lengthand shape of the compound composite conduit 166 formed, a technician maycouple the first end segment 134A of the first composite conduit 102 tothe first component 106A of the HVAC packaged unit 100, as discussedabove. Additionally, the technician may couple the fourth end segment134D of the second composite conduit 102B to the second component 106Bof the HVAC packaged unit 100. Accordingly, the first composite conduit102 is configured to extend between the first component 106A and thesecond composite conduit 102, and the second composite conduit 102 isconfigured to extend between the first composite conduit 102 and thesecond component 106B.

Looking more closely at the composite conduits 102, FIG. 8 is across-sectional schematic view of an embodiment of a portion of one ofthe composite conduits 102, in accordance with an aspect of the presentdisclosure. Because aluminum is approximately one third as dense ascopper, a greater thickness of material may be used for the aluminumconduit portions than for the copper conduit portions of the compositeconduit 102 to enable operation of the composite conduit 102 at desiredrefrigerant pressures of the HVAC packaged unit 100. For example, theillustrated embodiment of the main body 130 has a main body thickness168 that is greater than an end segment thickness 169 of the first endsegment 134A. In some embodiments, the main body thickness 168 is largerthan the end segment thickness 169 by 20%, 30%, 40%, 50%, 60%, or more.Although not presently illustrated, it should be understood that thesecond end segment 134B may also include the similar features describedherein with reference to the first end segment 134A.

The first end segment 134A has a first outer diameter 170A and a firstinner diameter 172A, and the main body 130 has a second outer diameter170B and a second inner diameter 172B. The outer diameters 170A, 170Bare substantially equal, such as within 5% of one another, therebyproviding a uniform exterior dimension or shape of the composite conduit102. However, because the second inner diameter 172B is less than thefirst inner diameter 173A, a stepped end segment transition 180 orstepped transition is formed between the first end segment 134A and themain body 130, in the present embodiment. Regardless of which directionthe refrigerant may flow within the composite conduit 102, the steppedend segment transition 180 may cause a small or negligible pressure dropin the refrigerant flowing through the composite conduit 102. Moreover,although illustrated as having a longitudinal end 184 of the first endsegment 134A coupled directly to a longitudinal end 186 of the main body130, it is to be understood that either longitudinal end 184, 186 mayalternatively be sized to receive and overlap the other longitudinal end184, 186 to facilitate more efficient copper-to aluminum brazing.

Additionally, because relative costs of copper and aluminum may varyover time, there may be a threshold price ratio above which employingthe composite conduits 102 is more cost-effective than employingsimilar, traditional copper interconnection conduits. For example, amanufacturer of the HVAC packaged unit 100 may implement the compositeconduits 102 if a ratio of a price of copper per pound to a price ofaluminum per pound is 2.0, 2.5, 3.0, or greater. During design of theHVAC packaged unit 100, the manufacturer may consider this relativematerial pricing with respect to a presently-recognized tradeoff. Thatis, the manufacture may consider and evaluate a decreased material costand weight of using the composite conduits 102 versus an decreasednumber of brazes and less complex manufacturing process for using thetraditional copper interconnection conduits. Based on analysis of thistradeoff, the manufacturer may implement the composite conduits 102 forsome or all interconnection conduits of the HVAC packaged unit 100.Additionally, the manufacturer may determine that composite conduits 102should be implemented for distances between components 106 that aregreater than a distance threshold.

FIG. 9 is a cross-sectional schematic view of another embodiment of aportion of the composite conduit 102, in accordance with an aspect ofthe present disclosure. Similar to the composite conduit 102 discussedwith reference to FIG. 8 above, the illustrated composite conduit 102includes the first end segment 134A having the end segment thickness 169that is less than the main body thickness 168 of the main body 130.However, instead of the stepped end segment transition 180 of FIG. 8 ,the present embodiment of the composite conduit 102 includes a smoothend segment transition 200 or smooth transition, which is taperedbetween the first inner diameter 172A of the first end segment 134A andthe second inner diameter 172B of the main body 130. As such, althoughthe manufacturing process for such a transition may include additionalprocessing steps, such as removing aluminum material from an innersurface 204 of the main body 130 to form a taper 206, the resultingcomposite conduit 102 may have a reduced pressure drop compared to thecomposite conduit 102 of FIG. 8 . In other embodiments, the first endsegment 134A may alternatively include a raised portion on an innersurface 208 of the first end segment 134A that forms the smooth endsegment transition 200. It should be understood that the connection ortransition between the first end segment 134A and the main body 130 mayinclude any suitable shape for directing refrigerant within thecomposite conduit 102.

Moreover, the present embodiment of the composite conduit 102 includes acorrosion resistant treatment 210 disposed over an outer surface 212 ofthe first end segment 134A and a portion of an outer surface 214 of themain body 130. The corrosion resistant treatment 210 may be any suitablecomponent or material that is configured to resist or prevent galvaniccorrosion that may otherwise occur at contact areas between twodifferent metals. In some embodiments, the corrosion resistant treatment210 is a heat shrink tape, a protective tube, or a coating. In someembodiments, the corrosion resistant treatment 210 is also applied to orextended over a connection between the first end segment 134A and theend joint 150 of a component 106. Moreover, it is to be understood thatthe corrosion resistant treatment 210 may be applied to any suitableportions of the composite conduit 102 or may be omitted, in otherembodiments.

Accordingly, embodiments discussed herein are directed to compositeconduits 102 or composite interconnection conduits that have a main body130 formed from aluminum and that have end segments 134 formed fromcopper. The aluminum end segments 134 may be pre-brazed onto respectiveends 136 of the main body 130, enabling technicians to couple thecomposite conduits 102 to copper connections of components 106 of theHVAC packaged unit 100 via copper-to-copper brazing techniques. Byutilizing lightweight aluminum for a significant length of the compositeconduits 102, the resulting HVAC packaged unit 100 may have a materialcost that is reduced by 10% or more compared to HVAC packaged unitshaving interconnection conduits formed entirely of copper. Indeed,because the tubing cost of HVAC packaged units 100 may account for 1%,2%, 3%, or more of the total cost of the HVAC packaged units 100, thematerial cost savings represent a significant cost benefit that mayoutweigh any manufacturing process complications involved withpre-brazing copper end segments 134 to the aluminum main body 130.

Moreover, the resulting HVAC packaged unit 100 has a reduced weightcompared to other HVAC packaged units. As such, an installer may replacea lower capacity, relatively lighter HVAC packaged unit on a rooftopwith the HVAC packaged unit 100 without implementing traditionalstructural reinforcements to the rooftop. In other embodiments, the HVACpackaged unit 100 may be manufactured with heavier heat exchange coilsthan a similar HVAC packaged unit without the composite conduits 102. Insuch embodiments, the weight savings provided by the composite conduits102 may be utilized to increase or optimize an operating capacity of theHVAC packaged unit 100 for its given weight. The lighter-weightcomposite conduits 102 may additionally enable the installer to use asmaller crane or other installation equipment when installing the HVACpackaged unit 100 in an operating position, thereby reducing overheadcosts associated with the HVAC packaged unit 100.

While only certain features and embodiments of the present disclosurehave been illustrated and described, many modifications and changes mayoccur to those skilled in the art, such as variations in sizes,dimensions, structures, shapes and proportions of the various elements,values of parameters, mounting arrangements, use of materials, colors,orientations, and so forth, without materially departing from the novelteachings and advantages of the subject matter recited in the claims.The order or sequence of any process or method steps may be varied orre-sequenced according to alternative embodiments. It is, therefore, tobe understood that the appended claims are intended to cover all suchmodifications and changes as fall within the true spirit of the presentdisclosure. Furthermore, in an effort to provide a concise descriptionof the exemplary embodiments, all features of an actual implementationmay not have been described, such as those unrelated to the presentlycontemplated best mode of carrying out the present disclosure, or thoseunrelated to enabling the claimed disclosure. It should be appreciatedthat in the development of any such actual implementation, as in anyengineering or design project, numerous implementation specificdecisions may be made. Such a development effort might be complex andtime consuming, but would nevertheless be a routine undertaking ofdesign, fabrication, and manufacture for those of ordinary skill havingthe benefit of this disclosure, without undue experimentation.

1. An interconnection conduit for a heating, ventilation, and/or airconditioning (HVAC) system, comprising: a main body comprising a firstinner diameter and a first conduit wall thickness, and the main body isformed from a first material; a first end segment secured to a first endof the main body, wherein the first end segment comprises a second innerdiameter greater than the first inner diameter and comprises a secondconduit wall thickness less than the first conduit wall thickness, andwherein the first end segment is formed from a second material differentfrom the first material; and a second end segment secured to a secondend of the main body, wherein the second end segment comprises a thirdinner diameter greater than the first inner diameter and comprises athird conduit wall thickness less than the first conduit wall thickness,wherein the second end segment is formed from the second material,wherein the interconnection conduit is configured to extend between afirst refrigerant circuit component and a second refrigerant circuitcomponent within an enclosure of the HVAC system and to directrefrigerant between the first refrigerant circuit component and thesecond refrigerant circuit component.
 2. The interconnection conduit ofclaim 1, comprising: a first stepped transition between the first innerdiameter and the second inner diameter; and a second stepped transitionbetween the first inner diameter and the third inner diameter.
 3. Theinterconnection conduit of claim 2, wherein the first end segment abutsthe first end of the main body to define the first stepped transition,and the second end segment abuts the second end of the main body todefine the second stepped transition.
 4. The interconnection conduit ofclaim 1, comprising: a first tapered transition between the first innerdiameter and the second inner diameter; and a second tapered transitionbetween the first inner diameter and the third inner diameter.
 5. Theinterconnection conduit of claim 1, wherein the main body comprises afirst outer diameter, the first end segment comprises a second outerdiameter, and the first outer diameter is substantially equal to thesecond outer diameter.
 6. The interconnection conduit of claim 5,wherein the second end segment comprises a third outer dimetersubstantially equal to the first outer diameter and the second outerdiameter.
 7. The interconnection conduit of claim 5, comprising acorrosion resistant treatment disposed on a first surface of the firstouter diameter and on a second surface of the second outer diameter,wherein the corrosion resistant treatment extends continuously from thefirst surface to the second surface at the first end of the main body.8. The interconnection conduit of claim 7, wherein the corrosionresistant treatment comprises heat shrink tape, a protective tube, or acoating.
 9. The interconnection conduit of claim 1, wherein the firstend segment is configured to be secured to a first end joint of thefirst refrigerant circuit component, and the second end segment isconfigured to be secured to a second end joint of the second refrigerantcircuit component.
 10. The interconnection conduit of claim 1, whereinthe first end segment is brazed to the first end of the main body, andthe second end segment is brazed to the second end of the main body. 11.The interconnection conduit of claim 1, wherein the first material isaluminum, and the second material is copper.
 12. An interconnectionconduit for a heating, ventilation, and/or air conditioning (HVAC)system, comprising: a main body comprising a first inner diameter,wherein the main body is formed from aluminum; a first end segmentcomprising a second inner diameter greater than the first innerdiameter, wherein the first end segment axially abuts a first end of themain body to define a first stepped transition between the first endsegment and the main body, and wherein the first end segment is formedfrom copper; and a second end segment comprising a third inner diametergreater than the first inner diameter, wherein the second end segmentaxially abuts a second end of the main body to define a second steppedtransition between the second end segment and the main body, and whereinthe second end segment is formed from copper. wherein theinterconnection conduit is configured to extend between a firstrefrigerant circuit component and a second refrigerant circuit componentwithin an enclosure of the HVAC system and to direct refrigerant betweenthe first refrigerant circuit component and the second refrigerantcircuit component.
 13. The interconnection conduit of claim 12, whereinthe main body comprises a first conduit wall thickness, the first endsegment comprises a second conduit wall thickness less than the firstconduit wall thickness, and the second end segment comprises a thirdconduit wall thickness less than the first conduit wall thickness. 14.The interconnection conduit of claim 13, wherein the main body comprisesa first outer diameter, the first end segment comprises a second outerdiameter, the second end segment comprises a third outer diameter, andthe first outer diameter, the second outer diameter, and the third outerdiameter are substantially equal to one another.
 15. The interconnectionconduit of claim 14, comprising a corrosion resistant treatment disposedon a first surface of the first outer diameter, on a second surface ofthe second outer diameter, and on a third surface of the third outerdiameter, wherein the corrosion resistant treatment extends continuouslyfrom the first surface to the second surface at the first end of themain body and extends continuously from the first surface to the thirdsurface at the second end of the main body.
 16. The interconnectionconduit of claim 15, wherein the corrosion resistant treatment comprisesheat shrink tape, a protective tube, or a coating.
 17. Theinterconnection conduit of claim 12, wherein the first end segment isbrazed to the first end of the main body, and the second end segment isbrazed to the second end of the main body.
 18. The interconnectionconduit of claim 12, wherein the first end segment is configured to bebrazed to a first copper end joint of the first refrigerant circuitcomponent, and the second end segment is configured to be brazed to asecond copper end joint of the second refrigerant circuit component. 19.An interconnection conduit for a heating, ventilation, and/or airconditioning (HVAC) system, comprising: a main body comprising a firstinner diameter and a first conduit wall thickness, wherein the main bodyis formed from aluminum; a first end segment secured to and axiallyabutting a first end of the main body to define a first steppedtransition between the first end segment and the main body, wherein thefirst end segment comprises a second inner diameter greater than thefirst inner diameter and comprises a second conduit wall thickness lessthan the first conduit wall thickness, and wherein the first end segmentis formed from copper; and a second end segment secured to and axiallyabutting a second end of the main body define a second steppedtransition between the second end segment and the main body, wherein thesecond end segment comprises a third inner diameter greater than thefirst inner diameter and comprises a third conduit wall thickness lessthan the first conduit wall thickness, and wherein the second endsegment is formed from copper, wherein the interconnection conduit isconfigured to extend between a first refrigerant circuit component and asecond refrigerant circuit component within an enclosure of the HVACsystem and to direct refrigerant between the first refrigerant circuitcomponent and the second refrigerant circuit component.
 20. Theinterconnection conduit of claim 19, wherein the first end segment isconfigured to be brazed to a first copper end joint of the firstrefrigerant circuit component, and the second end segment is configuredto be brazed to a second copper end joint of the second refrigerantcircuit component.